Preparation of Aluminosilicate Ferrierite Zeolite Nanosheets with Controllable Thickness in the Presence of a Sole Organic Structure Directing Agent.

Hao Xu,Yuxia Yu,Huizhen Wu,Hangling Zhai,Chao Shen,Chaoqun Bian,Longfeng Zhu,Jianying Tong

doi:10.3390/molecules25040771

Abstract

Preparation of aluminosilicate ferrierite (FER) zeolite nanosheets with controllable thickness in the presence of a sole organic ammonium is attractive, but still challenging. In this report, with the employment of N,N-diethyl-cis-2,6-dimethylpiperidinium (DMP) as both a structure directing agent and crystal growth inhibitor, aluminosilicate FER zeolite nanosheets, with a variety of crystal thicknesses, ranging from 6 to 200 nm, are successfully synthesized under hydrothermal conditions. Very interestingly, the amount of DMP in the starting gel is the key factor for crystal thickness control of aluminosilicate FER zeolite nanosheets. The obtained FER products, with different thicknesses, are well characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), N2 sorption, thermogravimetric analysis (TG), inductively coupled plasma (ICP), and magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. This simple strategy might provide a novel avenue for the synthesis of other zeolite nanosheets with controllable thickness.

Highlights

Zeolites, especially aluminosilicate zeolites, have been widely applied in the fields of adsorption, separation, ion exchange, and catalysis due to their uniform micropore distribution, large surface areas, and highly thermal and hydrothermal stabilities [1,2,3,4,5,6,7,8]
We report the synthesis of FER zeolite nanosheets with controllable thickness using a sole organic ammonium as both a structure directing agent and crystal growth inhibitor
The peaks at 9.3◦ associated with the [200] reflection widen with the increasing amount of DMP in the starting gel (Table 1), suggesting thinner thickness of FER zeolite along the [100] direction, which has been further confirmed by the results of the scanning electron microscopy (SEM) images (Figure 2)

Summary

Introduction

Especially aluminosilicate zeolites, have been widely applied in the fields of adsorption, separation, ion exchange, and catalysis due to their uniform micropore distribution, large surface areas, and highly thermal and hydrothermal stabilities [1,2,3,4,5,6,7,8]. From the viewpoint of the chemistry of zeolites synthesis, synthesizing the novel structures, developing the novel synthesis methodology, and controlling the morphology of zeolites are the main directions [9,10,11,12,13,14]. Among them, controlling the morphology of zeolites is a hot topic because of their improved properties in the process of application [15,16,17,18,19,20,21]. Li et al prepared mordenite (MOR) zeolite nanosheets with good catalytic performance in the dimethyl ether (DME) carbonylation due to the large amount of Brønsted acidic sites and fast mass transfer [24]

Methods

Results

Conclusion